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88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
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/* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
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#ifndef _CRIS_CHECKSUM_H
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#define _CRIS_CHECKSUM_H
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#include <asm/arch/checksum.h>
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/*
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* computes the checksum of a memory block at buff, length len,
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* and adds in "sum" (32-bit)
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*
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* returns a 32-bit number suitable for feeding into itself
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* or csum_tcpudp_magic
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*
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* this function must be called with even lengths, except
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* for the last fragment, which may be odd
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*
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* it's best to have buff aligned on a 32-bit boundary
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*/
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unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
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/*
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* the same as csum_partial, but copies from src while it
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* checksums
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*
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* here even more important to align src and dst on a 32-bit (or even
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* better 64-bit) boundary
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*/
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unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
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int len, unsigned int sum);
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/*
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* Fold a partial checksum into a word
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*/
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extern inline unsigned int csum_fold(unsigned int sum)
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{
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/* the while loop is unnecessary really, it's always enough with two
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iterations */
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while(sum >> 16)
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sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
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return ~sum;
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}
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extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
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int len, unsigned int sum,
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int *errptr);
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/*
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* This is a version of ip_compute_csum() optimized for IP headers,
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* which always checksum on 4 octet boundaries.
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*
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*/
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extern inline unsigned short ip_fast_csum(unsigned char * iph,
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unsigned int ihl)
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{
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return csum_fold(csum_partial(iph, ihl * 4, 0));
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}
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/*
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* computes the checksum of the TCP/UDP pseudo-header
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* returns a 16-bit checksum, already complemented
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*/
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extern inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
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unsigned long daddr,
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unsigned short len,
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unsigned short proto,
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unsigned int sum)
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{
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return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
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}
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/*
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* this routine is used for miscellaneous IP-like checksums, mainly
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* in icmp.c
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*/
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extern inline unsigned short ip_compute_csum(unsigned char * buff, int len) {
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return csum_fold (csum_partial(buff, len, 0));
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}
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#endif
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